”It is, however, not clear why the simple transference into garden soil should result in such a thorough and persistent revolution in the plant organism. No one will seriously maintain that in the open country the development of plants is ruled by other laws than in the garden bed. Here, as there, changes of type must take place if the conditions of life be altered, and the species possesses the capacity of fitting itself to its new environment. It is willingly granted that by cultivation the origination of new varieties is favored, and that by man’s labor many varieties are acquired which, under natural conditions, would be lost; but nothing justifies the assumption that the tendency to formation of varieties is so extraordinarily increased that the species speedily lose all stability, and their offspring diverge into an endless series of extremely variable forms. Were the change in the conditions the sole cause of variability we might expect that those cultivated plants which are grown for centuries under almost identical conditions would again attain constancy. This, as is well known, is not the case since it is precisely under such circumstances that not only the most varied but also the most variable forms are found.”

Gregor Mendel, “Experiments in Plant Hybridization”, 1865.

”Studying flowering potato fields in Peru has convinced me that all the so called local varieties can still be split into hundreds of forms….. in other words, there are millions of botanical varieties and forms. Our ignorance concerning the Andean potato diversity is striking….. There is a damned multitude of wild species, but the cultivated potato is such as I have never seen before, being still unacquainted with “the furnaces of creation”. And everything here is connected with wild materials….. I have been in Yucatan and now have a more or less full concept of the whole of South America….. I am collecting everything…”

Nikolai Ivanovich Vavilov, a letter to N.V. Kovalev sent from Peru on November 7, 1932.

The Instructions

1: Put together a good selection of seeds of different varieties. Heritage seeds are recommended because they don’t have any single-gene breeding potential that would throw off your results. The idea here is to get a broad genetic base to breed from.

2: Plant out the seeds. Let all of the pests and diseases do their worst in order that you can select the few plants most resistant to attack. The seeds can be planted with quite a close spacing since they will be thinned by disease pressure. It’s important to make sure that every plant gets infected, so that they all have an equal chance to show their resistance levels. Before the plants flower you can rescue the best survivors. You may have to apply a little organically approved crop protection to save them if they are very badly infected.

3: Crossbreed the winners. If they are separated from any other plants of the same crop, you can just remove the less hardy plants from your plot and let the best ones be naturally pollinated. The key is to make sure that they aren’t being crossed with plants from outside the selection group. Keep in mind that bees can forage over a range of several kilometers if food is in short supply.

4: Keep the seeds from these plants and use them to repeat the process next year.

Depending on how many seeds you start with — and how lucky you are — you might get an excellent variety right away; or it might take a number of generations of breeding. Statistically, maximum disease resistance will be reached after ten to fifteen generations of mass selection, though it’s quite likely that you’ll get some good varieties much earlier in the breeding process.